1. Field:
This invention relates to fluid valves and more particularly to fluid valves that have pressure relief means for relieving pressure from the downstream side of the valve to the upstream side.
2. State of the Art:
In cold climates, water that remains in outside water faucet pipes will occasionally freeze, sometimes causing breakage of the pipes. To rectify this problem there are freeze valves in which the faucet opening or spigot is outside the structure or house (e.g.), but the valve seat/gate arrangement is located within. An outside handle opens or closes the valve by means of a rod connecting the handle to the valve.
Ideally, with this arrangement, any water remaining in the pipe on the downstream side of the valve seat/gate arrangement will drain from the valve through the outside spigot. The water on the upstream side of the valve will ideally be located sufficiently within the outer wall of the structure to be kept fluid (avoid freezing) by the normal heat within the structure.
Occasionally, however, the water in the downstream portion of the pipe will not drain out of the spigot. For example, if a hose is connected to the spigot on the outside of the structure, or if the pipe has an upward slope, water may remain in the downstream pipe. Water may then freeze in the pipe and break the pipe and/or the valve. Serious flooding and damage may then occur.